Air conduction hearing aid having adjacently mounted microphone and receiver



May 9, 1950 L. G. WEAVER ET AL AIR CONDUCTION HEARING AID HAVINGADJACENTLY MOUNTED MICROPHONE AND RECEIVER Filed Oct. 25, 1946 2Sheets-Sheet 1 INVENTORS. Jazz/reuse G [11%1/ y Humbert May 9, 1950 G.WEAVER ET AL AIR CONDUCTION HEARING AID HAVING ADJACENTLY MOUNTEDMICROPHONE AND RECEIVER Filed Oct. 25, 1946 2 Sheets-Sheet'2 PatentedMay 9, 1950 UN IT'ED" STATES PATENT OFFICE.

AND RECEIVER LawrenceG Weaven. Evans ton, 111., and- Humbert Milani,Gary, Ind.

Application October 25, 1946, Serial No. 705,724

3 Claims. 1

This invention relates to devices, commonly termed hearing aids,intended for use by persons having defective or impaired hearing, andhas to do with devices of this character of the air con.- d-uction type.

In hearing aids of the character referred to, a receiver, in the generalnature of a telephone receiver and of which there are various types, ismounted on an insert positioned in the ear and having a projectionfitting into the auditory canal. The insert has a passage thereinopening through the inner end of theproj ection and comr'nunicating withthe output of the receiver, so that an air column is provided which isvibrated in accordance with the diaphragm or analogous element of thereceiver. Two types of inserts are commonly used. 'In one-type; theinsert is molded from an impression taken from the external ear and theouter or entrance portion of the auditory canal, so as to fit snugly inposition within the ear. The other type of insert commonly used is theplug type. It is in the form ofa short tube, which may have a rubber tipprovided with one or more annular vanes or flanges, for insertion intothe auditory .canal, there being an enlarged head at the outer end ofthe tube with provision for mounting the receiver thereon.

The receiver is mounted at the .outer end or face of the insert and isreadily observable. Many personsrequiringthe use of hearing aids arequite sensitive on the subject and refuse to use such devices, eventhough needed, since they have a feeling that the receiver and theinsert together are quite prominent and attract undesired attention.Since the receiver is mounted on theinsert, at the outer end thereof,itis necessary that itbe made as small as possible, for two reasons.Firstly, by having the-receiver as small as possible, the unsightlrojection, at the side of the head, provided by the-receiver, is kept:as small as possible, rendering it less diiiicultthan would other,- Wisebeithe case to persuade persons to wear-such devic s....SecQnd1y,thereceiver, ev n tho h as smallas practicallypossiblapossesses appreciable w i ht an s a r zcaus displacem nt or losenesS cf theinsertin th car Wh n tha oc feed backtakes place, withresultant squealing which grea ly mu -rsthe effici y of the-d vi e.Further, when the receiver is made quite small,- it has but littleoutputvolume with corresponding loss ingefiiciency, :frequently necessitatingoperation of the transmitter unitat high-power, which may causeobjectionable .distortionas 'well as objectionable batteryzdrainage.,Also, inconstructmg a verysmallreceiver,great careris required inmaking and assembling the parts, which is time consuming and expensive,and it often is extremely difficult, or practically impossible, to-con--struct such a receiver with the precision necessary to assure maximumeiiiciency.

The receiver, in the known hearing aid devices above referred to, isconnected by two fine Wires,

in the form of a cord, to the terminal contacts- Thatnecessitates at ofthe transmitter unit.- least eight contacts, two sets of four each, oneset at the receiver end of the cord and one set at the transmitter unitend. of the cord. Unless all ofthe contacts of the respective sets areaccurately matched looseness and slippage between the contacts is apt tooccur, causing objectionable noise and materially impairing the,efiiciency .of the device. In addition, the wires themselves are asource of trouble and expense. They are necessarily quite fine, for thesake of appearances, and are rather expensive to make. These wiresfrequently break and have to be replaced, which is an item ofappreciable expense to the user, aside from the inconyenience of partialor complete disability of the device ,dueto a broken wire. The wiresare, of course, coyerecl with suitable insulation and the rubbingtogether of the wires causes static which renders it diificult tounderstand what is .being said. Also, rubbingof the wires, or of U1? 9 3fi ii fi th 115. l h l ar i larly silk, -ireg ue ntly worn ,by women,causes obi le st ti When a re brea t ends the q ma be h l i loos conta tby e closin n ulat en and a Slight m o of h a d w l ca s bbin t e h o hn of t wi p duc n use i r qus n e n with hearing. If a wire breaks orbecomes exposed d a en th r eei t ma som in ntact with the users neck,causing repeated burns, the cumulative effect of which may be a seriousburn, which may become infected from the wire, and there are numerouscases where that has oc curred. In that connection, the transmitter unitcommonly is grounded to its enclosing metallic casing, and a circuit canbe completed from a broken or exposed wire in contact with the usersbody, particularly if perspiration be present, as in warm weather. Thereis, also, the risk that the wires may become exposed, due to rubbingoffv of the insulation, and come into contact with each other, causing ashortand seriously interfering with the use of the device. Also, in suchcases, there is risk that the exposed wires may come in contact with thebody and cause burns, even though the transmitter unit is enclosed in anonconductingcasi-ng formed of. plastic, as is done in some devices.Though there are numerous objections to the use of wires from thetransmitter unit to the receiver, no one prior to the instant inventionhas been able to dispense with such wires and they have been accepted asa neces sary evil.

The instant invention is directed to the provision of a simple andinexpensive hearing aid device in which the receiver may be disposedremote from the ear, concealed by the users clothing or apparel, and maybe of comparatively large size, and the necessity of providing wiresextending from the transmission unit to a receiver adjacent the ear ofthe user is eliminated. More specifically, under the present inventionthe receiver is mounted on and operatively connected to the transmitterunit, and the output of the receiver is connected by an enclosed aircolumn, conveniently by means of a tube of appropriate length, to thepassage of the ear insert. By eliminating the Wires, the numerousdifficultie incident to the use of such wires are eliminated, as well asthe expense of such wires, in the first instance, and frequent renewalthereof. Also, the contacts associated with such wires and the receiverare greatly reduced, or completely eliminated, correspondingly reducing,or eliminating, difficulties due to the presence of such contacts. Bydisposing the receiver at the transmitter unit, it may be ofcomparatively large size, which is conducive to increased accuracy andreduced cost of production. Further, a receiver of large size has muchgreater output volume than the small size receivers presently used and,even when used with a tube of considerable length, gives much betterresults, both as to volume and clarity than a small sized receivermounted directl on the ear insert. A further advantage of the instantinvention, is that it enables the use of an ear insert which ispractically invisible, or substantially so, thus avoiding theobjectionable projection beyond the side of the head, encountered in theprior hearing aid devices, currently used, above referred to. Furtherobjects and advantages of the instant invention will appear from thedetail description.

In the drawings:

Figure 1 is a front view of the head and shoulder portions of a manwearing hearing aid means embodying the instant invention, with the headshown in about three-quarters front view;

Figure 2 is an inner side or back view of the transmitter unit, with theremovable closure member of the casing omitted, and the receiver mountedthereon in accordance with the instant invention, on an enlarged scalerelative to Figure 1, the transmitter unit and associated parts beingdrawn to actual size thereof;

Figure 3 is an inner side or back view of the upper portion of thetransmitter unit of Figure 2, on the same scale as the latter figure,with the upper portion the back wall of the casing removed to show themounting chassis and associated parts;

Figure 4 is a combined side view, on an enlarged scale, of the receiverand associated parts mounted on the chassis, with the latter shown butfragmentarily, and sectional View of the connector member mounted on thereceiver and of the ear insert and the tube connecting it to theconnector member;

Figure 5 is an inner face view of the receiver of Figure 4;

Figure 6 is a view similar to Figure 3 but show 4 ing a modificationwith respect to the position and mounting of the receiver;

Figure '7 is a sectional view of the transmitter unit casing, takensubstantially on line i'! of Figure 6, the chassi and the parts carriedthereby being shown in elevation, this view also showing in elevationthe connector member mounted on the receiver and, fragmentarily, thetube extending therefrom;

Figure 8 is an outer face view of the receiver and the connector memberenclosed within an air sealing member, mounted on the back plate of thechassis, showing a second modification;

Figure 9 is a sectional view taken substantially on line S9 of Figure 8,the back plate of the chassis and the receiver and the connector memherbeing shown in elevation;

Figure 10 is an outer face view of the receiver and the connector membermounted on the back plate of the chassis, showing a third modification;and

Figure 11 is a sectional view taken substantially on line H-H of Figure10, certain parts being shown in elevation.

Preferably, though not necessarily, the ear insert used in the instantinvention is similar to the insert disclosed in the copendingapplication of Lawrence G. Weaver, Serial No. 634,597, for Hearing aid,filed December 12, 1945. The insert is molded from an impression takenof the external ear and the outer portion of the auditory canal, fitsnugly within the car so as to be effectively retained therein, ispreferably formed of a transparent or flesh colored plastic material,and when positioned in the ear is not readily visible. Within thebroader aspects of the instant invention, however, any suitable earinsert may be used.

In Figures 1 and 4, there is shown an ear insert I5, preferably similarto the mold insert disclosed in the above identified copendingapplication of Lawrence G. Weaver, as noted. The inse t I5 is providedwith an inwardly extending tubular projection l5 having therein apassage ll opening through its inner end. When the insert I5 is properlypositioned in the ear, the projection l6 fits snugly into the entranceportion of the auditory canal, into which the inner end of passage ITopens, and the outer end of passage I! opens through the then upperportion of insert IS. The insert I5 is then positioned well Within theexternal ear, as shown in Figure 1, so as to be hardly visible and, infact, cannot easily be detected if formed of transparent or fleshcolored material.

A flexible tube I8 has one end portion thereof suitably secured in theouter end portion of passage ll of ear insert I5. The other end portionof tube [8 is suitably secured in a short duct or passage IQ of a discshaped connector member 20. An exteriorly knurled ring 2|, of brass orother suitable material, is embedded in connector member 29 and definesa bore or recess 22 opening through one side face thereof. This bore 22opens, at its inner end, into a recess or air chamber 23 formed inconnector member 20, which air chamber 23 is connected with tube It!through an opening or notch 24 in ring 2 i. A split clamp spring 25 ismounted in ring 2!, adjacent the outer end thereof, in an interiorcircumferential groove 26 formed therein. The clamp spring 25 providesmeans for attaching the connector member 20 to a receiver, as will beexplained presently.

In Figures 2 and 4 there is shown a receiver 28 suitable for use withthe hearing aid of the in- .stant invention. Ibis :rec.eiver :28 :is :or:known type, 3 and is :in. the: form of :a .discxprovided at mic sidewith a central output ;studi2 9 jhaving are.- stricted neck. The outerface :of receiver :28 lfiat, as isthe inner; face of connector:member29, so that the latter seats flatwise on 1receiver 28. iltwill beunderstood that by Pressing connector member 29 toward receiver 28,tthestud .29 BK- .pands the clamp spring :25 .sufiiciently to pass.therethrough, after which this spring contracts about the :restricted,neck 6,! aofistudg'zfi. thereby detachably securing theconnectormemberzdto receiver .28 seating thereon, as above. )AS -:isshown in Fi ure 4, {the deptnof:theidepressionzin member .20, defined bythebore 2210f ring :2! and by theair chamber 23,:is greater thanthe:height of stud 29, providing outward therebeyond :the chamber 23,whichopens freely :into tube l8. There is thus provided enclosed iaircolumn extending from chamber -23 and the output of receiver 28 topassage of projection oritubular element 16 Of the-ear insert l5,passage ,l'irQpen- .ing into the auditory canal of the ear, when insert-'l;-5ris -positionedin the ear in the manner 'described above.

The receiver 23 is provided, at ,its'inner side, with two spacedprojections 01211135232 defining between them a dove-tailed groove. Thisgroove receives a cooperating mounting block ;33 suitably secured onaplate 34 of a chassis or mounting :frame 35 of atransmitter unit-3d.The block :33 is provided with two terminal Contact members whichcooperate with two similar contact members carried by the receiver 28,for operatively connecting the latter to the transmitter unit 36,

when receiverfifi is properly mounted on block 32, as is known.

The connector member as maybeiormed of any suitable material, butpreferably is formed of a known plastic and is either transparent orflesh colored. The tube l8 preferably is formed ofa suitable plasticsuch as Vinylite, ,though iitzmay be formed of rubber, aeit-her naturalor :syn- .thetic, or of any other suitablematerial, and iszpreierablyeither transparent or flesh-colored.

The transmitting .unit 3 6 is, :asanotedm'fknown type and a briefdescription thereof will sufiice. It comprises a metallic casing 31 inthe upper portion of which is mounted a chassis 35 carrying amicrophone, amplifying means including electron tubes, means foradjusting the power output of the amplifier, and associated elements. AB battery 38 and an A battery 39 are appropriately mounted in the lowerportion of casing 31, to which they are grounded, these batteries havingat one end contact with suitably disposed contact tabs, or fingers,carried by the chassis 35, the latter being secured to the back wall ofcasing 31 by a screw it which serves as a ground connection. The lowersection of the back wall of casing 3'? is in the form of a removablecover, to give ready access to the batteries and permit of removal andreplacement of the chassis 35, as may be required. The front wall ofcasing 36, at the upper portion thereof, is in the form of a grill Work42 which is disposed in overlying relation to the microphone of thetransmitter unit '36. While a transmitter unit, such as that illustratedand above described, by way of example, is preferred, any suitabletransmitter unit may be used within the broader aspects of the instantinvention.

In the use of the hearing aid device of the instant invention, theinsert I5 is properly positioned within the ear and the tube I8 is ledupwvard over irthe rear thence downwardiunder wearers clothing :to theconnector member :20, which 'mounted upon the :receiver 18 :at the :backcfithe'transmitter unit .135. Theinsert l5, when positioned'iin'thegear,cannot easily be detected and the tube l 8, whichmreferably,is:eithertransparent :ortintedz flesh color,;d0es not. attract attention, whilethe receiver ,is -.disposed I at the backer? the transmitter unit:3t,-*which unit :may :be :more or floss completely concealed. The de-'vice,;as awhole, isimno respect-conspicuous being, :in fact,substantially invisible, and may :be worn "with icomfort. By having thereceiver mounted directly; oirthe transmitter-unit thetube .id-may :beof sufiicient length ito permit of disposing the transmitter at. any.desiredposition on the body, while assuring adequate volume and ,high'clarity :of sound transmission through the tube :l,3,:since thereceiver 28 may bemade of any desired size, as-limited only :bythesizerof theunit -36, with the advantages previously mentioned withrespect to volume and clarity. By mounting .the receiver 123 -,on :thetransmitter unit '35, the necessity for wires extendingfromtheytransmitter to a receiver positioned adjacent the :ear is elimi-.nated, thereby eliminating the numerous difficulties 'encounteredin theuse of such wires above pointed out. If desired, a fine 'wire'may bepassed-through tube 48 and anchored at its ends to the earv insert liand the connector'member 20, with a view to resisting tension to whichtube -18 mightotherwise be-subjected inuse. Under ordinary conditions,the tube l8 possesses adequate mechanical strength and such areinforcing wire 15111013 required. Also, if-desired,-the tube [8 may beof reduced interior diameter at .the portion thereof adjacent the .earinsert .15, which may be desirable in certain .cases -:as conducive toincreasedclarity ;0f hearing-though ordinarily that is-not-required.

.In the modification-shown in Figures 6 and 7, the mounting block 3.3:of Figures 3 and 4 is omitted and the receiver 2% is mounted-directlyon plate :34 of chassis 35, with appropriate oper- .ative connection tothe transmitter and amplifier unit, as will bereadily understood.Preferably the depth of casing .s fia, from front to back thereof, issuflicient to accommodate the receiver 28, the back wall of casing 35ahaving therein an opening 36b of a size to accommodate the connectormember 20. By mounting the receiver 28 directly on plate at of chassis35, with direct connection to the transmitter and amplifier unit, thenecessity for providing contacts for operatively connecting the receiverto the transmitter unit is eliminated, thereby avoiding the difficultiesincurred with respect to such contacts, above mentioned. By disposingthe receiver 28 within casing 36a, it is substantially enclosed andguarded thereby against injury, which is advantageous. A screw iterpasses through the back wall of casing 36:; and threads into a memberassociated with plate 34a, providing a ground connection, as before.

When the receiver is positioned on, or closely adjacent to, thetransmitter unit there may be, in certain cases, air leakage resultingin squealing and whistling, interfering, to an objectionable extent,with clarity of hearing. Such a leakage may occur, particularly if theconnector member 26 is loosely mounted on the receiver 28. In order toguard against leakage between the re ceiver and the connector member 29,these two members may be enclosed within a container or bag #2, formedof rubber or like material impervious to air, this bag 42 being sealedabout the tube 18. If air leakage should occur between the member 20 andreceiver 28, the air pulsations or vibrations escaping into the bag 42will be effectively damped out or killed thereby so that feed back willnot occur.

In the modification shown in Figures 10 and 11, the receiver 28a isprovided with an exteriorly threaded output stud 29a, on which theconnector member a, is screwed, there being a sealing gasket 44 betweenthis member and the receiver 280.. The gasket 44 is formed of suitablerubberlike material, or any suitable material, assuring an airtight sealbetween the connector member 20a and the receiver 28a. As will beunderstood, the member 20a is provided with an air chamber 23a beyondthe outer end of stud 29a, communicating by way of a short passage orduct 19a with tube [8. By screwing the connector member 20a into tightseating contact with gasket 44, air leakage between the connector member20a and the receiver 28a is effectively prevented, thus eliminating riskof feed back and resultant squealing or whistling.

What is claimed is:

1. In hearing aid means, a transmitter unit intended to be positionedremote from the earcomprising a protective casing and a chassis therein,a receiver on said chassis operatively connected to said unit, aconnector member defining an air chamber mounted on said receiver withthe output of the latter opening into said air chamber, an ear inserthaving an extension disposed to fit into the auditory canal of the earwhen said insert is positioned therein and a passage opening through theinner end of said extension, a fiexible tube secured at one end to saidconnector member opening into said chamber and secured at its other endto said insert opening into said passage, and closure means sealing saidreceiver and connector member against escape of air therefrom exceptthrough said tube.

2. In hearing aid means, a transmitter unit intended to be positionedremote from the ear comprising a protective casing and a chassistherein, a, receiver on said chassis operatively connected to said unit,a connector member defining an air chamber mounted on said receiver withthe output of the latter opening into said air chamber, an ear inserthaving an extension disposed to fit into the auditory canal of the earwhen said insert is positioned therein and a passage opening through theinner end of said extension, a flexible tube secured at one end to saidconnector member opening into said chamber and secured at its other endto said insert opening into said passage, and an airtight member sealedabout said receiver and connector member eifective for preventing escapeof air therefrom except through said tube.

3. In hearing aid means, a transmitter unit intended to be positionedremote from the ear comprising a protective casing and chassis therein,a receiver on said chassis operatively connected to said unit providedat its outer side with an outwardly extending threaded output stud, aconnector member defining an air chamber threaded on said stud with thelatter opening into said chamber, said connector member seating on saidreceiver with an airtight seal therebetween, an ear insert having anextension disposed to fit into the auditory canal of the ear when saidinsert is positioned therein and a passage opening through the inner endof said extension, and a flexible tube secured at one end to saidconnector member opening into said chamber and secured. at its other endto said insert opening into said passage.

LAWRENCE G. WEAVER. HUMBERT MILANI.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,253,656 Williams Jan. 15, 19181,318,874 Hooghiemstra Oct. 14, 1919 1,412,539 Murray Apr. 11, 19221,601,063 Frederick Sept. 28, 1926 2,419,471 Thibes Apr. 22, 1947

